Burner that creates uniform flame size by using progressively smaller holes



PIERCE BURNER THAT CHBATES UNIFORM FLAME SIZE BY Jan. 16, 1968 USING PROGRESSIVELJY SMALLER HOLES '2 Sheets-Sheet 1 Filed July 15, 1965 INVENTOR. EUGENE E. PIERCE O0OOOOOOOWOOOnY OO UOOOOOOOOOOOOOO OOOOO ATTORNEYS Jan. 16, 1968 E. E. PIERCE BURNER THAT CREA'I ES UNIFORM FLAME SIZE BY USING PROGRESSIVELY SMALLER HOLES 2 sh ets-sheet 2 Filed July 15, 1965 Q E m R. m m O E 8 m5 vw NN 3 E w r u OOOOOOOO OOOOOAA ATTORNEYS United States Patent Ofi 3,363,845 Patented Jan. 16, 1968 ice 3,363,845 BURNER THAT CREATES UNIFORM FLAME SIZE BY USING PROGRESSIVELY SMALLER HOLES Eugene E. Pierce, Cleveland, Ohio, assignor to Lincoln Brass Works, Detroit, Mich, a corporation of Michigan Filed July 15, 1965, Ser. No. 472,285 Claims. (Cl. 239-559) ABSTRACT OF THE DISCLOSURE Burner tube has two oppositely disposed longitudinal series of burner ports. Top of tube is taper-flattened to progressively diminish sectional area of tube in a downstream direction. The flattening also progressively flattens and decreases the effective areas of the downstream ports. Purpose is to compensate for velocity and static pressure differential of fuel gas flowing in the tube. Downstream end of tube is closed by complete flattening and is shaped as a mounting bracket.

Disclosure Numerous conventional burners for gas range ovens are essentially tubes provided with burner porting which extends a considerable distance alon the tube. The fuel gas is introduced into one end of the tube. The velocity of the fuel gas adjacent the upstream burner porting is greater than at the downstream porting, while to the contrary, the static pressure of the gas is greater at the downstream porting than at the upstream porting. This results in relatively small flames at the upstream end of the burner, relatively larger flames at the downstream end, and a consequent uneven distribution of heat within the oven.

It is conventional to deal with this problem by varying the effective sectional area of the burner tube along its length, or varying the effective size of the burner ports, or by providing a burner tube of such a size that it acts as a uniform static pressure reservoir, or by combinations of these three approaches. However, prior structures for carrying out these approaches have been relatively bulky and/ or expensive and numerous of them have not worked satisfactorily.

The object of the present invention is to provide a relatively simple, inexpensive, small, and lightweight burner structure and method of its manufacture, the structure being improved so that flames issuing from it along its entire length are of substantially uniform size.

Generally, the invention'contemplates the use of a metal tube having a series of burner ports along a major portion of its length. The metal of the tube is distorted adjacent the downstream burner ports to provide a gradually increasing partial flattening of the tube which progressively decreases both the sectional area of the tube and the effective sizes of the burner ports in the flattened region.

The downstream end of the tube is completely flattened to provide a substantially gas-tight seal. The flattened end of the tube is shaped to provide a bracket for connection with a support within an oven. One form of the invention is shown in the accompanying drawings.

FIG. 1 is a generally side elevational view of a burner according to this invention.

FIG. 2 is an enlarged sectional view on line 22 of FIG. 1.

FIG. 3 is an enlarged. partly diagrammatic, sectional view on line 3-3 of FIG. 1.

FIG. 4 is a further enlarged, fragmentary, generally elevational view looking in the direction of arrow 4 in FIG. 3.

FIG. 5 is an enlarged sectional view on line 5-5 of FIG. 1.

FIG. 6 is a generally side elevational. view of a tube from which the burner is made.

FIG. 7 is a generally side elevational view of the tube after a Venturi has been formed therein.

FIG. 8 is a generally side elevational view of the tube after the burner ports have been provided therein.

FIG. 9 is a partly diagrammatic, fragmentary view, partly in side elevation and partly in section, illustrating at step in forming the downstream end portion of the tube.

FIG. 10 is a view similar to FIG. 9, but illustrating the step of shaping the flattened end of the tube to form a bracket.

Shown in FIG. 1 is a burner 20 according to the present invention comprising a burner tube 22 having an open upstream end 24- into which fuel gas is injected and a downstream end portion which is flattened and shaped to form a bracket 26 which engages a support 28 within a gas range oven (not shown). Bracket 26 may, in some installations, be anchored in place by such means as a screw 30 and in other installations may be merely loosely engaged over the support.

The upstream end portion 24 of tube 22 is longitudinally slotted to provide primary air openings 32, the effective size of which is controlled by a rotatable shutter cap 34 secured in adjusted position by a screw 36. Adjacent the primary air openings, the burner tube is provided with a Venturi restriction 38 which opens downstream into the burner tube proper.

Adjacent the Venturi and for some distance downstream thereof, burner tube 22 has a circular sectional shape. Beginning at a location 49, the top of tube 22, as FIG. 1 is viewed, is tapered inwardly at an angle to the tube axis and the tapered portion adjoins bracket 26. The opposite side falls of tube 22 are each provided with, a longitudinally extending series of burner ports 42 which are close enough together to be in mutually igniting relation. The two series of ports are interconnected by a flame runner port which comprises an angled slot 44 (FIG. 1).

The portion of tapered region 46 which extends adjacent ports 42 has a length 4 (FIG. 1) which is preferably in the range from about one-third of the total length of the series of ports to about two-thirds the length thereof. Tapered portion 46 of the tube has side portions 48 which adjoin opposite side walls 49 of the tube and which has a central portion 50 which is dished inwardly of a chord extending between junctures 48 (FIG. 3) for a purpose to be described.

Shown in FIG. 6 is a length of tubing 52 from which burner 20 is made. This tubing can be either seamless or of the type in which flat strip stock is bent to circular shape and its edges secured together along a longitudinal seam by a fused metal connection. One example of suitable tubing is of the latter type having an outer diameter of about /8" and a wall thickness of about .035", the tubing being made of steel and being aluminized for corrosion resistance. This tubing is subjected to a die operation in which Venturi restriction 38 is formed, the excess metal forming vanes 54 which can be disposed at any angular orientation to meet the space and support requirements of a particular oven structure. In the burner illustrated. these vanes are angled to the general plane of ports 42 (FIGS. 1 and 5).

The two series of ports 42 are provided in the side walls of tubing 52. (FIG. 8) by any suitable drilling or punching operation. After ports 42 have been provided in the tubing, the downstream end portion thereof is tapered inwardly at 46 by suitable mechanism such as dies '56, 58. These die may be configured to completely flatten that portion 64) of tubing 52 which extends downstream of taper 46 and ports 42. This flattening provides a substantially gas-tight seal. Flattened portion 69 is then subjected to whatever further shaping operation may be necessary to provide bracket 26, and this shaping may be accomplished by such means as clamps '62, 64 and dies 65, 66. Runner port 44 and primary air slotting 32 may be provided at any convenient time during the process of manufacture. When shutter cap 34 and screw 36 are added, the burner is complete.

By tapering portion 46 of the tube inwardly, the effective sectional area of the tube is gradually decreased in the region of the downstream one-third to two-thirds of the series of ports 42. Moreover, the inward distortion of the tube causes a distortion of the metal defining the ports adjacent taper 46, and this results in progressively decreasing the effective sizes of the ports in a downstream direction. This decrease in effective port sizes is illustrated in exaggerated form in FIG. 3 wherein ports 42a in the tapered portion of tube 22 are smaller than ports 42 in the circular portion of the burner tube. From FIG. 3, it will be seen that the decrease is caused by a change in the shape of the port: The port dimension in a direction perimetrical about the tube axis is decreased while the port dimension longitudinal of the tube remains substantially unchanged. By way of example, where ports 42 have a diameter of .070", ports 42a gradually decrease to an effective size of .065" diameter.

The tapering of tube portion 46 is esentially a flattening operation. However, the tapered portion is dished inwardly somewhat at 50 as described above. The reason for this is to limit the departure of the axes of ports 42a angularly from the axes of ports 42. Referrng to FIG. 3, it will be apparent that if dishing 50 were not provided, the distance between junctures 48 would be greater and the axes of ports 42a would depart further than shown from the axes of ports 42. Thus, the dishing facilitates substantially uniform flame disposition when the burner is in operation. While this dishing has hen found advantageous in burners now in use, it may not be required in all burners according to this invention.

In use, it may be assumed that burner 20 has been installed in an oven with bracket 26 engaging support 28 and with the outlet of a fuel gas source (not shown) aligned with burner inlet 24. Fuel gas entering burner tube 22 has a relatively high velocity and low static pressure near Venturi 38 and a lower velocity and higher static pressure in tapered region 46. However, tapering 45 and the gradual decrease in the size of ports 4120 progressively increases resistance to the flow of gas through the downstream ports. This gradual increase in resistance compensates for the velocity and static pressure differential along the tube with the result that the amount of gas exiting the ports along the two series is substantially uniformly distributed heat.

Bracket 26 may have any desired shape and, for example, in certain installations might be left flat as. at 60 (FIG. 9). Burner port 44 is disposed at an angle (FIG. 1) to avoid a concentration of heat adjacent the furthermost upstream ports 42.

I claim:

1. A burner for gas range ovens and the like comprisa metal tube having an upstream end portion provided with a fuel gas inlet,

said tube having a first wall portion with a series of burner ports extending longitudinally of said tube downstream of said inlet,

said tube having a second wall portion angularly displaced about the tube axis from a plurality of the ports in a downstream portion of said series,

the metal of said tube being distorted so that said second wall portion, progressing in a. downstream direction, is angled toward the axis of said tube so that both the sectional area of the tube portion thereat and the effective sizes of said plurality of burner ports progressively decrease in a downstream direction, said tube having a downstream end portion downstream of said series of burner ports, and means providing a closure for said downstream end portion,

said tube having substantially circular cross-section upstream of the distorted portion, said distortion comprising, in general, a flattening of said second wall portion,

said second wall portion having side portions which adjoin said first wall portion,

said second wall portion between said side portions thereof being dished inwardly of a chord extending between the junctures of said side portions with said first wall portion.

2. A burner for gas range ovens and the like comprising,

a metal tube having an upstream end portion provided with a fuel gas inlet,

said tube having a first wall portion with a series of burner ports extending longitudinally of said tube downstream of said inlet, said tube having a second wall portion perimetrically displaced, about the tube axis, from a plurality of ports in a downstream portion of said series,

portions of the metal of said tube being bent so that said second wall portion, progressively in a downstream direction, is angled toward the tube axis with consequent progressive decrease of the sectional area of the tube, and progressive increase in the dimension of said tube lateral of said axis, said bent portions extending to and including a region of said first wall portion containing said plurality of (ports with consequent constriction of said) ports,

said ports in said region, as a consequence of being in said bent portions, being changed in shape, said change comprising a decrease of the port dimension in a direction perimetrical about the tube axis with the port dimension longitudinal of the tube remaining substantially unchanged so that the effective port area is decreased,

said change in shape and consequent decrease in port area, progressing in said downstream direction, being progressively greater,

said tube having a downstream end portion downstream of said series of burner ports and means providing a closure for said downstream end portion.

3. The burner defined in claim 2 wherein said tube has substantially circular cross section upstream of the distorted portion,

said first wall portion including two oppositely disposed wall portions each containing a said series of ports, said second wall portion extending between and adjoining said oppositely disposed wall portions,

said distortion comprising, in general, a flattening of said second wall portion,

said second wall portion being dished inwardly of a chord between its junctures with said oppositely disposed wall portions,

said distorted portion extending from the downstream end of said series upstream for a distance which is in the range of from about one-third to about twothirds of the length of said series.

4. A burner for gas range ovens and the like comr prising,

a metal tube having an upstream end portion provided with a fuel gas inlet,

said tube having a first wall portion with a series of burner ports extending longitudinally of said tube downstream of said inlet,

said tube having a second wall portion perimetrically displaced, about the tube axis, from a plurality of ports in a downstream portion of said series, said second wall portion having side portions which adjoin said first wall portion,

the metal of said tube being distorted so that said second wall portion, progressively in a downstream direction, is angled toward the tube axis with consequent progressive decrease of the sectional area of the tube, and progressive increase in the dimension of said tube lateral of said axis,

said second wall portion between said side portions thereof being dished inwardly of a chord extending between the junctures of said side portions with said first wall portion,

said distortion extending to and including a region of said first wall portion containing said plurality of ports with consequent constriction of said ports,

said constriction, progressing in said downstream direction, being progressively greater so that the effective sizes of said plurality of ports progressively decrease,

said tube having a downstream end portion downstream of said series of burner ports and means pro viding a closure for said downstream end portion.

5. A burner for gas range ovens and the like comprising,

a metal tube having an upstream end portion provided with a fuel gas inlet,

said tube having two oppositely disposed first wall portions, each containing a series of burner ports extending longitudinally of said tube downstream of said inlet, said tube having a second wall portion perimetrically displaced, about the tube axis, from a plurality of ports in a downstream portion of said series, said second wall portion extending between and adjoining said oppositely disposed wall portions,

the metal of said tube being distorted so that said second wall portion, progressively in a downstream direction, is angled toward the tube axis with consequent progressive decrease of the sectional area of the tube, and progressive increase in the dimension of said tube lateral of said axis,

said tube having substantially circular cross-section upstream of the distorted portion, said distortion comprising, in general, a flattening of said second wall portion,

said second wall portion being dished inwardly of a chord between its junctures with said oppositely disposed wall portions,

said distortion extending to and including regions of said first wall portions containing said plurality of ports with consequent constriction of said ports,

said constriction, progressing in said downstream direction, being progressively greater so that the effective sizes of said plurality of ports progressively decrease,

said distorted portion extending from the downstream ends of said series upstream for a distance which is in the range of from about one-third to about twothirds of the length of said series,

said tube having a downstream end portion downstream of said series of burner ports and means providing a closure for said downstream end portion.

References Cited UNITED STATES PATENTS 807,245 12/ 1905 Clamond 158114 X 843,653 2/-1907 Wofili 158-114 X 1,077,073 10/1913 Hook 158-114 X 1,451,072 4/1923 Hoffstetter 158-114 X 2,541,428 2/1951 Leo et al. 239--416.5 X 3,270,967 9/1966 Westerman et al 239-560 3,285,318 11/1966 Keinonen et al. 158114 FOREIGN PATENTS 519,539 1/1921 France. 999,357 10/ 1951 France.

18,688 1912 Great Britain.

M. HENSON WOOD, JR., Primary Examiner. V. C. WILKS, Assistant Examiner. 

